Lever type mainspring winding device for clock



Nov. 3, 1970 MASANORI KOBAYASHI 1 3,537,254

LEVER TYPE MAINSPRING WINDING DEVICE FOR CLOCK I Filed Match 19, 1969 72 sheets-sheet 1 Nov. 3, 1970 Q MASANIORIZ KbYASl-li 7, I

LEVER T YPE MAINSPRING WINDING DEVICE FORCLOCK Filed March 19; 1969 2Sheets-$heet z a FIG. 3

FIG.4

United States Patent Japan Filed Mar. 19, 1969, Ser. No. 809,483 Claimspriority, appltiea/ltziim Japan, Mar. 21, 1968,

Int. Cl. G64b 3/00 US. Cl. 58-46 12 Claims ABSTRACT OF THE DISCLOSURE Alever-type mainspring winding device comprising a ratchet wheel rotatedby a feed pawl, a detent mounted to a winding lever and having thecentral angle formed by both meshing positions of said feed pawl andsaid detent with said ratchet wheel corresponding to the value obtainedby subtracting a smaller angle than the central angle subtended by onetooth of said ratchet wheel from an angle an integral number of times aslarge as the central angle subtended by one tooth of said ratchet wheel,thereby providing the winding lever with a free play angle through whichit can move unaffected by the unwinding force of the mainspring.

BACKGROUND OF THE INVENTION 1.Field of the invention This inventionrelates to a device for winding a mainspring by means of a lever in aspring-operated clock.

2.Description of the prior art In a spring-operated clock in which alever-type mainspring winding device is incorporated, it is preferred,for the sake of appearance, that the finger engaging part of the levernot be allowed to project outwardly from the cover of the clock too far,while on the other hand, in order to facilitate the winding operation ofthe stem, the knob of the stem must protrude far enough from the coverof the clock to be easily engaged by the users finger. The prior artlever-type mainspring winding devices are provided with a foldable ornestable lever and have the disadvantage that the lever tends to causeback-lash and to be damaged. Moreover, folding or contraction andextension of the lever is troublesome. This makes the winding operationof the mainspring of a clock encased in a tachograph more troublesome.

SUMMARY OF INVENTION This invention makes it possible to obviate theabovedescribed disadvantages inherent in the conventional devices andprovides a novel and improved lever-operated mainspring winding device.

This invention makes it possible to provide a levertype mainspringwinding device in a clock of the type wherein a mainspring is fixed atone end to a barrel and at the other end to a first wheel arbor. Thedevice comprises a ratchet wheel fixed to a first wheel arbor, a stempivotally mounted concentrically with said first wheel arbor, a feedpawl engageable with said ratchet wheel for rotating the ratchet wheelin response to the pivoting of said winding lever, a detent inengagement with said ratchet wheel for the prevention of reverserotation of the ratchet wheel, and a central angle formed by bothmeshing positions of said feed pawl and said detent with said ratchetwheel corresponding to the value obtained by subtracting an anglesmaller than the central angle subtended by one tooth from an angle anintegral number of times larger than the central angle subtended by oneice tooth of said ratchet wheel. Thus, while the detent is preventingthe ratchet wheel from being reversely rotated by the unwinding force ofthe mainspring, the feed pawl is freely swung within the range of a freeplay angle, which is an angle smaller than the central angle subtendedby one tooth of said ratchet wheel, whereby the winding lever isinitially allowed to pivot a predetermined distance without being placedunder the action of the mainspring. Accordingly, in the initial stage ofthe mainspring winding operation, the winding lever can be readily movedto a position in which it is easy to catch by the users fingers withinthe range of said free play angle, thus making it possible to firmlycatch the lever prior to the actual winding of the mainspring. Windingof the mainspring is effected by the lever being pivoted within therange of the angle left by subtracting said free play angle from thetotal pivotal angle of the lever. After the mainspring has been wound,the winding lever may be left in any position within the range of thefree play angle of the lever.

An object of the invention is to provide a lever-type mainspring windingdevice for a clock which is both easy to operate and durable instructure.

Another object of the invention is to provide a levertype mainspringwinding device which does not mar the appearance of a clock.

These and other features, advantages and objects of the presentinvention will become more apparent from the following description withreference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a side view, broken in part, of atachograph incorporating a clock therewith;

FIG. 2 is a rear view of the clock portion;

FIG. 3 is an enlarged rear view of the clock portion, revealed byremoval of a part of the back covering;

FIG. 4 is an enlarged section taken along line IVIV of FIG. 3; and

FIG. 5 is a section taken along line V-V of FIG. 4.

DETAILED EXPLANATION OF PREFERRED EMBODIMENT Referring now to thedrawings and in particular to FIG. 1, a front lid 2 is pivotallyconnected by a hinge 3 to a casing 1 of a cylindrical tachograph, and awatch mechanism 4 covered with a cylindrical back cover 5 is provided onthe backside of said front lid 2.

A first wheel arbor 6 is supported for rotation on a base plate 7 insidesaid cover and on a supporting plate 8 which is fixed to free columns 9in an eccentric position of said cover 5as shown in FIGS. 2, 3 and 4.One end of said arbor 6 protrudes from the backside of said cover 5. Acylindrical barrel 10 is rotatable and concentrically fitted over saidfirst wheel arbor 6. A mainspring 11 encased in the barrel 10 is mountedat one end to the barrel 10 and at the other end to the first wheelarbor 6, respectively.

A winding ratchet wheel 12 is fixed to a square shaft portion of thefirst wheel arbor rearwardly of said supporting plate 8. Rearwardly ofsaid ratchet wheel 12 a hub 13 is rotatably fitted over the first wheelarbor 6, a segment or oscillation plate 14 is fixed to the front portionof the hub 13, and a manually operable winding lever 15 is fixed to therear portion of the hub 13 protruding outwardly of the cover 5. A nut 16is screwed into the rear end of said wheel arbor 6.

A feed pawl of winding click 17 for rotating the ratchet wheel 12 isrotatably supported by a pin 18 protruding from the front of the segment14 and is normally pressed, by a hair spring 19, mounted on segment 14,into engagement with ratchet wheel 12, while a detent 20 is rotatablysupported by a pin 21 which protrudes from the back of supporting plate8 and is normally pressed into engagement with ratchet wheel 12 by ahair spring 22 mounted to the supporting plate. The pin 18 extendsdownwardly so as to come into contact with the edge of the supportingplate 8, while the other pin 21 extends upwardly so as to come intocontact with the edge of the segment 14. These pins 18 and 21 determinethe angle of oscillation of said segment 14 and consequently the rangeof movement of winding lever 15 and depending upon their particularplacement, the range of movement of winding lever 15 be regulated. Thesegment 14 is normally biased in a counterclockwise direction as seen inFIG. 3, by a weak return spring 23 fixed at one end to the base plate 7.

The central angle of one ratchet tooth is the angle which that toothsubtends as shown in FIG. 5, and for the ratchet wheel 12 shown, whichhas 18 teeth, the central angle 5 would 'be 20. The central anglebetween the two meshing positions of feed pawl 17 and detent 20 with theratchet wheel 12 is set at an angle corresponding to the value obtainedby subtracting an angle smaller than the central angle subtended by oneratchet tooth from an angle an integral number of times larger than saidcentral angle. As shown, the central angle is 167 and is found bysubtracting an angle of 13", which is the free play angle and smallerthan the central angle of 20, from the central angle of 180, which isnine times 20 since the two meshing positions are set 9 teeth apart.Because of this, when the detent 20 is in mesh with the ratchet Wheel 12thereby preventing the ratchet wheel from being reversely rotated thefeed pawl 17 slides on the tooth surface of the ratchet wheel 12 withoutbeing subjected to the unwinding force of the mainspring within therange of the angle of 13 and is therefore freely swingable. Thus, thewinding lever 15 is allowed to freely swing in the angular range fromthe position in which the pin 18 is in contact with the supporting plate8, namely from an original position 0, as shown in FIG. 2, to theposition away by said free play angle (13) from the original position,namely to a starting position S, and winding of the mainspring 11 iseffected by pivoting the winding lever 15 from said starting position Sto the position in which said pin 21 is in contact with the segment 14,namely to a terminal position T.

As shown in FIGS. 1 and 2, said winding lever 15 is placed in a recess24 formed on the back of cover and the position of the unwinding leverwith respect to the cover 5 is such that, when the winding lever ispivoted to the terminal position T, the longitudinal direction of thelever is in alignment with the radial direction of the cover, and whenthe winding lever is pivoted back to its original position, the foremostend of the lever is in approximate alignment with the periphery of thecover. Accordingly, during movement of the winding lever to effectwinding of the mainspring, the foremost end of the stem graduallyprotrudes outwardly of the periphery of the cover 5 until it protrudesat the starting position S sufficiently to be caught by the usersfingers and protrudes most in the terminal position T.

Winding of the mainspring is operated in the following manner. The lid 2of a tachograph is opened to expose the backside of the clock 4. Thedistal end of winding lever 15, which is now in its original position 0,is pressed outwardly by the users finger to be placed in the startingposition S. In this position, the winding lever is again fingered at itsdistal end and pivoted or swung reciprocatingly between the startingposition S and the terminal position T.-It should be noted that in theterminal position T, winding lever coincides with the radial directionof back side cover 5. During the forward motion of said reciprocatingswing, a segment 14 is rotated in a clockwise direction in FIG. 3 androtates a ratchet wheel 12 clockwise thereby winding a mainspring 11.During the reverse 'motion of said reciprocating swing, a detent keepsthe ratchet wheel 12 againstmovement in a counter clockwise directionand the feed pawl 17 returns to its original positionfAft'er windingofthe'mainsprin'g has been completed, release of the fingers from thewinding lever allows the return spring 23 to draw said lever 15 to itsoriginal position. As the spring 23 is weak, it sometimes happens thatthe winding lever does not return to its original position and in such acase, the lever may be returned to its original position by the usersfinger.

The restoration of the wound-up mainspring 11 is transmitted to otherordinary mechanisms (not shown) through a first wheel 25 provided on theperiphery of the barrel 10.

What is claimed is:

1. A device for winding a spring comprising; ratchet means mounted forrotation, drive means releasably engaging said ratchet means forrotating said ratchet means, hold means releasably engaging said ratchetmeans for preventing rotation of said ratchet means, said drive meansand said hold means being positioned with respect to each other in theirrest position such that the central angle formed by both engagingpositions corresponds to the value obtained by subtracting an anglesmaller than a central angle subtended by one ratchet tooth from anangle an integral number of times larger than said ratchet tooth centralangle.

2. A device as defined in claim 1, wherein said drive means comprises afeed pawl pivotally mounted on a first pin, lever means pivotallyconnected to said first pin for actuating said feed pawl, and said holdmeans comprises a detent pivotally mounted on a second pin.

3. A device as defined in claim 2, including a mounting plate, meansmounting said lever means for relative movement with respect to saidmounting plate.

4. A device as defined in claim 3, wherein said mounting plate iscylindrically shaped.

5. A device as defined in claim 3, wherein said lever mounting means iseccentrically positioned with respect to the geometrical center of saidmounting plate.

6. A device as defined in claim 4, wherein said lever means ispositioned relative to said mounting plate such that when the levermeans is in its terminal position, it coincides with the radialdirection of said mounting plate.

7. A device as defined in claim 4, wherein said lever means ispositioned relative to said mounting plate such that when lever means isin its original position, its distal end is in alignment with theperiphery of said mounting plate.

8. A device as defined in claim 2, including means for variably settingthe range of movement of said lever means.

9. A device as defined in claim 3, wherein said mounting plate comprisesa cover housing.

10. A lever-type mainspring winding device comprising a wheel arbormounted for rotation, a ratchet wheel fixed to said wheel arbor, a hubrotatably supported on said wheel arbor, a winding lever connected tosaid hub, feed pawl means positioned to releasably mesh with saidratchet wheel, means connecting said feed pawl means to said hub wherebymovement of said winding lever imparts rotation to said ratchet wheelthrough said feed" pawl means, a detent positioned to releasably meshwith said ratchet wheel, said feed pawl means and said detent beingpositioned with respect to each other in their rest position such thatthe central angle formed by both meshing positions corresponds to thevalue obtained by subtracting an angle smaller than the central anglesubtended by one ratchet tooth from an angle an integral number of timeslarger than said ratchet tooth central angle.

11. A device as defined in claim 10, including spring means for nonnallybiasing said winding lever to its original position.

12. A lever-type mainspring winding device for use in a timepiececomprisingra wheel arbor mounted for rotation, a ratchet wheel fixed tosaid wheel arbor, a hub rotatably supported on said wheel arbor, awinding lever connected to said hub, feed pawl means positioned toreleasably mesh with said ratchet wheel, means connecting said feed pawlmeans to said hub whereby movement of said winding lever impartsrotation to said ratchet wheel through said feed pawl means, a detentpositioned to releasably mesh with said ratchet wheel, said feed pawlmeans and said detent being positioned with respect to each other intheir rest position such that the central angle formed by both meshingpositions corresponds to the value obtained by subtracting an anglesmaller than the central angle subtended by one ratchet tooth from anangle an integral number of times larger than said ratchet tooth centralangle, whereby said winding lever is pro- 15 185-39; ss s1 vided with afree play angle through which it can move unaffected by the unwindingforce of the mainspring.

References Cited UNITED STATES PATENTS RICHARD B. WILKINSON, PrimaryExaminer L. R. FRANKLIN, Assistant Examiner U.S. Cl X.R.

